Republicans who had supported new rules for Wall Street expressed concern yesterday about a fee on banks and hedge funds that has been added to the bill, complicating the measure’s prospects for passage. ... The death yesterday of West Virginia Democratic Senator Robert Byrd, and Wisconsin Democrat Russell Feingold’s refusal to back the final package, underscored the need for some Republican support to obtain 60 votes necessary to proceed to final Senate action on the financial-regulatory bill approved June 25 by a House-Senate committee.